Hemangiopericytoma in children and infants

BACKGROUND. Hemangiopericytoma (HPC) is a soft-tissue neoplasm most commonl y seen in adults; only 5-10% of cases occur in children. Childhood HPC comp rises two distinct clinical entities. In children older than 1 year, it beh aves in a manner similar to adult HPC. Infantile HPC, however, although his tologically identical to adult HPC, has a more benign clinical course. The reasons for these differences in the natural history of HPC are not well un derstood. METHODS. The authors reviewed the clinicopathologic features of MPC as well as the treatment and outcomes of the 12 children (9 males and 3 females) t reated for this disease at St. Jude Children's Research Hospital over a 35- year period. RESULTS. At diagnosis, 9 patients were older than 1 year and 3 were younger than 1 year. Among the 9 older patients, tumors were most commonly found i n the lower extremities (n = 5). One patient had been treated for acute lym phoblastic leukemia 15 years earlier. One patient had metastatic disease at diagnosis, and three had unresectable tumors. Two patients experienced obj ective responses to chemotherapy. Three patients died of disease progressio n. Among the three infants, two had unresectable disease at diagnosis, and both experienced excellent responses to neoadjuvant chemotherapy. In one ca se, the response of the turner to chemotherapy correlated with maturation t o hemangioma. All three infants are alive without evidence of disease. CONCLUSIONS. HPC in children older than 1 year does not differ from adult H PC, and aggressive multimodality therapy is required. Infantile HPC, on the other hand, is characterized by better clinical behavior, with documented chemoresponsiveness and spontaneous regression, and requires a more conserv ative surgical approach. In some cases of infantile NPC, this benign behavi or correlates with maturation to hemangioma. Cancer 2000;88:198-204, (C) 20 00 American Cancer Society.